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Propranolol, a beta-blocker, is a widely used drug for cardiovascular diseases. A synthetic sample containing propranolol (PRO) solution at native pH was recirculated up to ten times through an original coaxial non-thermal plasma reactor with a water falling film. Different discharge conditions, feed gasses, and power greatly influenced the extent of PRO degradation and the abundance of degradation products. The highest degradation rates were achieved in Ar plasma, either pure or in a mixture with O2, with over 70% of PRO degraded after only two passes through the DBD reactor. The full non-thermal plasma treatment was followed by a minimal change of pH value and conductivity. On the other hand, ambient air as the feed gas resulted in 60% of PRO degradation rate after the full treatment and contributed to a major drop in pH value and an increase in the conductivity of the treated solution. The structures of 47 degradation products in all three gases were identified and the degradation pathway is proposed, supported by DFT methodology. Scavenging experiments demonstrated that hydroxyl radical was predominant when plasma was generated using ambient air and Ar, while it had a minimal effect on the degradation in the mixture of Ar and O2. The desired level of propranolol decomposition was achieved only by the adjustment of the nonchemical parameters of the treatment, such as plasma gas composition and power. These results imply that a non-thermal plasma reactor is a highly effective method for pharmaceutical wastewater treatment, with no catalysts added.

Pharmaceuticals represent a considerable threat when they reach the environment. Propranolol (PRP), designed to be a biologically active compound, is a widely used beta-blocker prescribed for heart-related diseases. Due to its frequent use, PRP is detected in numerous aquatic environments and organisms. To completely remove pharmaceuticals such as PRP, advanced oxidation processes (AOPs) are often employed, like ozone, or electrochemical oxidation. Recently, the non-thermal plasma treatment has gained interest for water purification, due to in situ production of reactive oxygen species, such as hydroxyl radicals and superoxide anion radicals. The aim of this paper was to investigate plasma treatment for PRP removal from water. To achieve that, the dielectric barrier discharge (DBD) non-thermal reactor was used. This DBD reactor was already tested for degradation of different organic compounds. In this study, PRO solution (100 mg/dm3) was recirculated through the DBD reactor, while plasma was generated using ambient air and argon. The PRP degradation rate was monitored on HPLC-DAD, and the specific energy density (SED) was used to compare plasma effects on PRP degradation. SED was calculated by dividing the power (kept at 35 W and multiplied by the number of cycles of treatment) by the flow rate (held constant at 7.5 dm3/h). The single most striking observation is that pure argon contributes to faster PRP degradation. Namely, at 75 kJ/dm3, there was less than 5% of PRP left when treated with Ar non-thermal plasma, while only around 35% was achieved at the same point with ambient air. As for the degradation products, several compounds were identified (P326, P308, P292, P266, and P134). Interestingly, all compounds were spotted in air-treated PRP solution, but P326 and P308 were not found in samples treated by Ar-generated plasma. In summary, both decomposition rate experiments and detected degradation compounds imply that Ar may be a better plasma gas for PRP treatmen

Propranolol (PRO) is a beta-blocker that is readily detected in surface water and hospital wastewater. This pharmaceutical poses a danger for aquatic animals because it is commonly prescribed for heart diseases and anxiety issues. Advanced oxidation processes are commonly tested for the decomposition of pharmaceuticals because they produce various reactive species at room conditions. A liquid-falling film dielectric barrier discharge (DBD) reactor was used for the treatment of a PRO solution, with no catalysts added. A coaxial construction, accompanied by a peristaltic pump, enables the recirculation of the treated liquid. Ambient air was selected as a feed-gas for nonthermal plasma generation under three levels of power dissipated in plasma. Direct contact of liquid film with plasma in this coaxial reactor enables the efficient transfer of reactive oxygen and nitrogen species generated in plasma to the liquid phase. The degradation rate of PRO, pH value, and conductivity were monitored after every cycle of treatment of PRO solution (100 mg/dm3), and in the presence of scavengers (t-butanol and p-benzoquinone). The PRO concentration was monitored by HPLC-DAD, at 213 nm. As expected, the highest applied power (60 W) contributed to the highest degradation rate (100%). At the same time, in these extreme conditions, pH values dropped from 6 to 2.5 and conductivity increased from 20 µS/cm to almost 1450 µS/cm in the tenth cycle of plasma treatment. Moreover, a high power yielded an excessive decontamination level, but also in the grand production of nitric acid. On the other hand, lower values of power lead to less successful endpoints, over 85% and less than 60% of degraded PRO when 35 W and 15 W were applied, respectively. Accordingly, under these conditions, the total production of ions was less intensive. The maximum conductivity value was less than 500 µS/cm for PRO treated with plasma generated by 35 W of power, and under 130 µS/cm for 15 W. To elude the exact role

Propranolol hydrochloride (PRO, Fig. 1), beta-blocker, is poorly degradable in wastewater treatment plants. Because of its wide use, it could pose a threat to aquatic organisms and water users. [1] The non-thermal plasma reactor (Fig. 2) is tested for degradation of propranolol hydrochloride solution (100 ppm), using different gases under the same electrical conditions (35 W of power dissipated in plasma). The concentration of PRO in samples was quantified using HPLC-DAD (213 nm), with acetonitrile and water (70/30 V/V) as eluents. The retention time of PRO was 5.100 min. The most successful propranolol hydrochloride degradation was achieved using Ar with O2 (80/20 V/V), applying 35 W of power dissipated in plasma, almost 80 % in the 1stcycle of treatment (Fig. 3). The best results with air are slightly over 80 % but in the 10th cycle of plasma reactor treatment. The presence of N2 in the air decreases the availability of reactive oxygen species, as shown in [2]. This non-thermal plasma is successful at the degradation of organic pollutants in water, such as propranolol hydrochloride, under given conditions. The level of propranolol hydrochloride degradation can be increased modifying the composition of feed gas, with best results using Ar with O2.

Chemical properties of distilled water treated by non-thermal plasma reactor were studied. Hydrogen-peroxide production, pH value and conductivity in distilled water were measured after plasma-treatment in air, argon and argon-oxygen mixture as working gases. Water falling film dielectric barrier discharge (DBD) reactor 1 was used for water treatment. Direct contact of water film with plasma in this reactor enables efficient transfer of reactive species generated in plasma to liquid phase. For optimization of reactive species production frequency and amplitude of the applied voltage were varied. Chemical characterization of water treated by DBD generated in different gases shows that hydrogen peroxide production in argon reaches yield of 0.78 g/kWh, while in air it was 0.19 g/kWh. Both measurements were made with 35 W of power dissipated in plasma. Moreover, significant influence of gas atmosphere was observed in measurements of pH value and conductivity which imply that production of ions is about 15 times greater in water treated with plasma generated in air than in argon. Advanced oxidation using this type of non-thermal plasma reactor enables production of active species in situ, while working in ambient conditions.1 Effectiveness of plasma treatment was already confirmed with degradation of some waterborne pharmaceuticals.2 This opens opportunities for new studies of plasma oxidation of pharmaceuticals in aquatic environments.

Ova doktorska disertacija posvećena je istraţivanju dielektričnog barijernog praţnjenja u kontaktu sa vodom i njegovim primenama. U dielektričnom barijernom praţnjenju (DBP) sa padajućim vodenim filmom ispitana je interakcija plazme i tečnosti sa karakterizacijom fizičkih i hemijskih osobina gasne i tečne faze. Osnovni doprinos ovog istraţivanja je unapreĎenje razumevanja hemijskih procesa koje neravnoteţna plazma na atmosferskom pritisku indukuje u tečnostima. Plazma u DBP reaktoru ispitivana je uz pomoć emisione spektroskopije i električnih merenja. Ispitano je formiranje hidroksil radikala (˙OH) i dugoţivećih hemijskih vrsta (H2O2, O3, NO3 i NO2 ) u vodi i dimetil sulfoksidu koji su izloţeni delovanju neravnoteţne plazme u DBP reaktoru sa vodenim filmom u zavisnosti od gasne atmosfere (vazduh, azot, kiseonik, argon i helijum). U fokusu ovog istraţivanja bilo je formiranje hidroksil radikala i mogući uticaj njegovog zahvatanja hemijskom sondom (dimetil sulfoksid) na formiranje dugoţivećih vrsta. UtvrĎeno je da reakcija rekombinacije hidroksil radikala suštinski odreĎuje formiranje vodonik-peroksida u praţnjenjima u vazduhu, azotu i argonu. Za prostorno- vremensko istraţivanje interakcije plazme sa vodom korišćen je helijumov plazmeni mlaz u kontaktu sa vodom. Snimci razvoja praţnjenja dobijeni iCCD kamerom otkrivaju da interakcija praţnjenja sa tečnom metom moţe biti produţena nekoliko puta u zavisnosti od radnih parametara. Merene su raspodele emisije nekoliko ekscitovanih hemijskih vrsta da bi se identifikovao glavni mehanizam ekscitacije. Korišćenjem metoda Štarkove polarizacione spektroskopije, izmerena je raspodela jačine električnog polja u plazmenom mlazu koji interaguje sa tečnom metom. Ova merenja podrţana su Šlirenovom vizuelizacijom plazmenog mlaza i vodene mete. Pokazano je da neznatne promene neelektričnih parametara, kao što je udaljenost mete i brzina protoka gasa, mogu u potpunosti da promene prirodu praţnjenja. Merene vrednosti električnog polja s, The subject of the presented thesis is the study of dielectric barrier discharge in contact with water and its applications. In water falling film dielectric barrier discharge (DBD) plasma- liquid interaction has been studied, with characterization of physical and chemical properties of the gas phase and the liquid phase. The main contribution of this research is improvement of understanding of chemical processes induced in liquids by nonthermal atmospheric/pressure plasmas. Plasma in DBD reactor has been studied by optical emission spectroscopy and electrical measurements. The formation of hydroxyl radical (˙OH) and long-living chemical species (H2O2, O3, NO3 and NO2 ) generated in water and in dimethyl sulfoxide in water falling film DBD in dependence on the gas atmosphere (air, nitrogen, oxygen, argon and helium) was studied. The focus of this study was the formation of hydroxyl radical and the influence of ˙OH scavenging by dimethyl sulfoxide on the formation of long-living species. It was found that formation of hydrogen peroxide in air, nitrogen and argon discharges is determined by recombination reaction of hydroxyl radicals. For spatio-temporally resolved study of plasma-liquid interaction helium plasma jet with liquid target was used. ICCD recordings of the discharge development revealed that discharge interaction with the target can be elongated several times, depending on the operating parameters. Distributions of the emissions of several excited chemical species are measured in order to identify the main excitation mechanisms. Utilizing the method of Stark polarization spectroscopy, the electric field strength distribution measurements in helium plasma jet interacting with a liquid target are also obtained. Measurements are supported by simultaneous Schlieren imaging of both the effluent of plasma jet and water target. It was shown that the slight change of the non-electrical parameters, such as target distance and the gas flow rate can completely change

Nicotine degradation efficiency in water solutions was studied using a water falling film dielectric barrier discharge (DBD) reactor. Two different treatments were applied: direct treatment, the recirculation of the solution through a DBD reactor, and indirect treatment, the bubbling of the gas from the DBD through the porous filter into the solution. In a separate experiment, samples spiked with nicotine in double distilled water (ddH(2)O) and tap water were studied and compared after both treatments. Furthermore, the effects of the homogeneous catalysts, namely, Fe2+ and H2O2, were tested in the direct treatment. Nicotine degradation efficiency was determined using high-performance liquid chromatography. A degradation efficiency of 90% was achieved after the direct treatment catalyzed with Fe2+. In order to analyze the biodegradability, mineralization level, and toxicity of the obtained solutions, after all degradation procedures the values of the following parameters were determined: total organic carbon, chemical oxygen demand, biochemical oxygen demand, and the Artemia salina toxicity test. The results showed that an increase in biodegradability was obtained, after all treatments. A partial nicotine mineralization was achieved and the mortality of the A. salina organism decreased in the treated samples, all of which indicating the effective removal of nicotine and the creation of less toxic solutions. Nicotine degradation products were identified using ultrahigh-performance liquid chromatography coupled with a linear ion trap Orbitrap hybrid mass spectrometer and a simple mechanism for oxidative degradation of nicotine in non-thermal plasma systems is proposed.

The formation of hydroxyl radical and long-living chemical species (H2O2, O-3, NO3- and NO2-) generated in the liquid phase of a water falling film dielectric barrier discharge in dependence on the gas atmosphere (air, nitrogen, oxygen, argon and helium) was studied. The chemical molecular probe dimethyl sulfoxide was employed for quantification of. OH, and the influence of hydroxyl radical scavenging on formation of reactive oxygen and nitrogen species was investigated. In addition to liquid analysis, plasma diagnostics was applied to indicate possible reaction pathways of plasma-liquid interaction. The highest. OH production rate of 1.19 x 10 (5) mol l (1) s (1) was found when water was treated in oxygen, with a yield of 2.75 x 10(-2) molecules of. OH per 100 eV. Formation of hydrogen peroxide in air, nitrogen and argon discharges is determined by recombination reaction of hydroxyl radicals, reaching the highest yield of about 0.7 g kWh(-1) when distilled water was treated in argon discharge. Ozone formation was dominant in oxygen and air discharges. Strong acidification along with formation of reactive nitrogen species was detected in water treated in air and nitrogen discharges.

Pharmaceutical compounds have been detected frequently in surface and ground water. Advanced Oxidation Processes (AOPs) were reported as very efficient for removal of various organic compounds. Nevertheless, due to incomplete degradation, toxic intermediates can induce more severe effects than the parent compound. Therefore, toxicity studies are necessary for the evaluation of possible uses of AOPs. In this study the effectiveness and capacity for environmental application of three different AOPs were estimated. They were applied and evaluated for removal of ibuprofen from water solutions. Therefore, two treatments were performed in a non-thermal plasma reactor with dielectric barrier discharge with and without a homogenous catalyst (Fe2+). The third treatment was the Fenton reaction. The degradation rate of ibuprofen was measured by HPLC-DAD and the main degradation products were identified using LC-MS TOF. Twelve degradation products were identified, and there were differences according to the various treatments applied. Toxicity effects were determined with two bioassays: Vibrio fischeri and Artemia salina. The efficiency of AOPs was demonstrated for all treatments, where after 15 min degradation percentage was over 80% accompanied by opening of the aromatic ring. In the treatment with homogenous catalyst degradation reached 99%. V. fischeri toxicity test has shown greater sensitivity to ibuprofen solution after the Fenton treatment in comparison to A. salina. (C) 2014 Elsevier B.V. All rights reserved.

In this study the effect of different homogenous catalysts and their dosage on mesotrione degradation in water falling film dielectric barrier discharge (DBD) reactor was investigated. Four catalytic systems Mn2+ /DBD, Co2+/DBD, Fe2+/DBD and H2O2/DBD were examined. In order to find optimal conditions various concentrations of catalysts and specific energy density (SED) values were tested in each system. Mesotrione degradation efficiency was determined by HPLC-DAD and mineralization efficiency by TOC value. Degradation products were identified by UHPLC-Orbitrap-MS and compared after finding out the optimal concentration for each catalytic system. All studied catalytic systems have proved to be successful in improving mesotrione removal, but the highest improvement in degradation efficiency was obtained with catalytic system 5 ppm Fe2+/DBD (by 50% for SED 124 kJ/L) and 10 mM H2O2/DBD for improving mineralization efficiency (by 45% for SED 310 kJ/L). Nine degradation products were identified in catalytic DBD treatments. Main degradation products were: glutaric acid, 2-nitro-4-methylsulfonylbenzaldehyde and 2-nitro-4-methylsulfonylbenzoic acid. H2O2/DBD gave significantly different degradation products than other catalytic systems. Dominant degradation products in other systems were not identified in system with hydrogen peroxide, which supported the fact that the highest mineralization efficiency was achieved with peroxide catalytic system. Global toxicity of samples after degradation in each system was determined using Artemia sauna and they could be considered as "non toxic".